This indicator provides a true volume surrogate based on tick volumes. It uses a specific formula for calculation of a near to real estimation of trade volumes distribution, which may be very handy for instruments where only tick volumes are available. Please note that absolute values of the indicator do not correspond to any real volumes data, but the distribution itself, including overall shape and behavior, is similar to real volumes' shape and behavior of related instruments (for example, currency futures).
The indicator shows the volumes as a histogram in two colors. The green color means that the volume of the current bar is larger than that of the previous one. The red color means that the volume of the current bar is smaller than the volume of the previous bar.
Parameters AlertSigmaFactor and ExtraAlertSigmaFactor (0 by default, meaning that alers are disabled) allow you to enable alerts when a volume exceeds any of the two predefined levels (main and additional). The values should be specified as a factor of standard deviations (for example 1.0 or 3.0) counted from the mean value on the available history. If both levels are non-zero, there can be two alerts on one bar, that is one alert of each kind. The levels are shown on the chart as horizontal lines (red and dashed).
The version of TrueVolumeSurrogate for MetaTrader 4 exists.